I guess you wonder why I look so blue
There's no one left to tell my troubles to
For when I say that soon I'll married be
The boys don't give me any sympathy
Each pal will take my had with tear-dimmed eye
And say "you poor old boob, goodbye"

Cheer up, the worst is yet to come
Wait 'til the wedding is over
Cheer up, the worst is yet to come
You for the cornfields and clover
No more roaming 'round with Broadway Queens
You'll be flirting with the old soup greens
Wifey dear will buy a book
Then she'll teach you how to cook
Cheer up, the worst is yet to come

I'm married now, I made this girl my wife
I'll have to serve my sentence now for life
Each day you read of battles 'cross the sea
Those soldiers have a cinch compared to me
Her mother came to live with us today
I made a kick and she did say

Cheer up, the worst is yet to come
Your bachelor days now are over
Cheer up, the worst is yet to come
Back to the cornfields and clover
Now you've got a shirt with buttons gone
Soon you'll have no shirt to sew them on
Lots of debts that you can't pay
Maybe twins are on their way
Cheer up, the worst is yet to come

This can be found on the album, Songs Of The Hill Country - Sacred And Native American Melodies.

Most of the song titles on the back of Saint Dude are references to older sheet music/songs. This one is an old ridiculous song from 1915 about how marriage is evil, and totally fits on these manly song collections. That said, "Cheer Up The Worst Is Yet To Come" is itself just a fairly famous phrase, and it's possible Beck was alluding to that, not this song.